After resetting everything and beginning from scratch everything seems to work now! Thank you so much for your help :)

@Rongzhong Li The attached screenshots show the settings I used when compiling the code. I did set the board to arduino Uno. Maybe another setting is wrong?

@Rongzhong Li I ordered it from Indiegogo and uploaded WriteInstinct.ino and ran the first calibration with the command 'YYY' with 'no line ending' and a baudrate of 115200. Then I uploaded OpenCat.ino for the final joint calibration. The attached screenshot shows the size.

Hi, I am using the latest code from Github. I am not sure how to check the size of the compiled file, but I do have some size information that the ArduinoIDE provided me. I am pretty new to Arduino robotics so I hope this is the information you need. I have also attached a video showing the behavior of Bittle after pressing the walk button. Thank you!